Circuit breaker with thrust transmitting operating mechanism



J@ 21, 1970 DE ANGELO ET Al. 3,492,614

CIRCUIT BREAKER WITH THRUST TRANSMITTING OPERATINGMECHANISM ATTORNEYJan. 27, 1970 G. J. DE ANGELO ET AL CIRCUIT BREAKER WITH THRUSTTRANSMITTING OPERATING MECHANISM 3 Sheets--SheeiI 2 Filed Jan. 18, 1968FIGA.

Jan. 27, 1970 G. J. DE ANGELO ETAL 3,492,514

CIRCUIT BREAKER WITH THRUST TRANSMITTING OPERATINGMECHANISM Filed Jan.18, 1968 3 Sheets-Sheet 3 FIGS.v

United States Patent O 3,492,614 `CIRCUIT BREAKER WITH THRUST TRANS-MITTING OPERATING MECHANISM Gerald J. deAngelo, Monroe, and Francis L.Gelzheiser, Fairfield, Conn., assignors to Westinghouse ElectricCorporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan.18, 1968, Ser. No. 698,891 Int. Cl. H01h 3/00, 73/.00

U.S. Cl. 335--191 10 Claims ABSTRACT OF THE DISCLOSURE A circuit breakercomprises an improved compact thrust-transmitting operating mechanism.The mechanism is constructed to move the handle intermediate the on andoff positions when the breaker trips to provide a visual indication thatthe breaker has tripped.

CROSS-REFERENCES TO RELATED APPLICATIONS Certain features of the hereindisclosed circuit breaker are disclosed in the co-pending patentapplications Ser. No. 698,848, filed Jan. 18, 1968 and Ser. No. 698,809,liiled Ian. 18, 1968.

BACKGROUND AND OBJECTS OF THE INVENTION For certain circuit breakerapplications, it is desirable to provide increased contact pressurewithout a highstrength overcenter spring mechanism that would makemanual operation difficult. Thus, an object of this invention is toprovide an improved thrust-transmitting operating mechanism forincreased contact pressure,

Another object is to provide an improved thrust-transmitting operatingmechanism with means for moving the handle of the circuit breaker to anintermediate position during tripping operations to provide a visualindication that the circuit breaker has tripped.

A further object of this invention is to provide a circuit breaker withan improved thrust-transmitting operating mechanism that is compact inconstruction.

SUMMARY OF THE INVENTION An improved circuit breaker comprises a rstlink pivotally connected to a contact arm and a second link pivotallyconnected to a latched trip structure. The rst and second links areconnected by means of a knee pivot, and a third link, which is pivotallyconnected to the knee pivot, is pivotally connected to a manuallyoperable operating member. The operating member operates through thethird link to thrust the toggle to an erected position moving thecontact arm to a closed position. A spring is provided below thestationary contact structure to provide contact pressure in the closedposition of the contacts. The operating member operates the third linkto collapse the toggle to effect an opening operation of the contactarm. The trip structure comprises an elongated releasable cradle or tripmember pivotally supported intermediate the ends thereof. The releasabletrip member is latched at one end by means of a trip device. The otherend of the releasable trip member is connected to the second toggle linkby means of a pivotally supported angle link. One leg of the angle linkis pivoted to the second toggle link and the other leg is connected tothe releasable trip member by means of a lost-motion connection. Duringtripping operations, the cradle is released to permit the upper pivotalconnection of the second toggle link and the angle link to move tothereby permit an opening movement of the contact arm. As the icecontact arm moves to the open position, the toggle collapses and theoperating member is moved to an intermediate position to provide avisual indication that the circuit breaker has tripped. During thetripping operation, the parts of the trip structure and operatingmechanism do not move to a substantially higher position within thehousing so that the height-wise dimension of the circuit breaker can bekept relatively small. The circuit breaker is reset by moving theoperating member to the full O position to ymove the releasable tripmember and link members to the reset position in which position thereleasable trip member is automatically latched by the trip device topermit manual operation of the circuit breaker. During closingoperations, the movable contact engages the stationary contact with atoe-and-heel engagement, and during opening operations the movablecontact leaves the stationary contact with a heel-and-toe disengagementwhereby the wear from Contact engagement and arcs occurs mostly on thetoe portion of the contact.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a top plan view of atwo-pole circuit breaker constructed in accordance with principles ofthis invention;

FIG. 2 is a sectional view taken generally along the line II-II of FIG.l showing the breaker in a closed position;

FIG. 3 is a View similar to FIG. 2, with parts broken away and with thebreaker in the oli position;

FIG. 4 is a View similar to FIG. 3 with the breaker in the trippedposition;

FIG. 5 is a sectional view, with parts shown in elevation and with partsbroken away, taken generally along the line V-V of FIG. 2; and

FIG. 6 is a view illustrating the connection between the releasable tripmember, angle-link and upper toggle link.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, thereis shown therein a circuit breaker 5 comprising an insulating housing 7and a circuit-breaker structure 9 supported on the housing 7.

The insulating housing 7 is a two-part housing comprising a base 11,having a generally planar bottom, and a cover 13 secured to the base 11by means of three rivets 15. The base 11, at one end thereof, comprisesinsulating barriers 17 forming two adjacent cavities. The cavities areopen at the top and open at the one end of the housing for receiving twoclamp-type terminals 19 that are used to connect conducting lines to thetwo-pole units. The terminals 19 are more specifically described in theco-pending patent application of Kenneth R. Coley, Ser. No. 698,809,tiled Jan. 18, 1968. The base 11 and cover 13 cooperate to form twoadjacent compartments 21 for housing the circuit breaker parts of thetwo pole units.

Each of the circuit-breaker structures 9 comprises an operatingmechanism 23, trip structure 25 and trip device 27. A separatecircuit-breaker structure 9 is supported in each of the compartments 21.

Since the parts of the two pole units of the circuit breaker areidentical, only the pole unit seen in FIGS. 2-4 will be specificallydescribed.

Referring to FIG. 2, the operating mechanism 23 comprises a stationarycontact 29 and a movable contact 31. The stationary contact 29 is xedlysecured to a rigid conductor 33 that extends toward the one end into acavity 35, formed in the base 11, where the conductor 33 is connected toor is part of a clip-on type terminal 37 that is supported in the cavity35. The cavity 35 is open at vthe bottom of the base 11 for receiving astab 'conductor that would protrude into the cavity 35 to be engaged bythe clip-on type connector 37. The movable contact 31 is fxedly securedto an elongated contact arm 39. The contact arm 39 is provided with aslot 41 therein for receiving a supporting pin 43. A torsion spring 45biases the one end of the contact arm 39 to the position seen in FIG. 3wherein the pin 43 is at the lower part of the slot 41. A toggle 47connects the contact arm 39 with an angle-link 49 of a trip structure51. The toggle 47 comprises a lower toggle link 53 and an upper togglelink 55. The lower toggle link 53 is pivotally connected to the contactarm 39 by means of a pin 57 and the upper toggle link 55 is pivotallyconnected to one leg of the angle-link 49 by means of a pin 59. Thetoggle links 53 and 55 are pivotally connected by means of a knee pivotpin 61. The angle-link 49 comprises two legs that are angularly spacedand movable as a unit. The angle-link 49 is mounted on a iixed pivot 63that is supported between a pair of rigid side plates 64 that aresupported in the associated compartment. Only one of the side plates 64is seen in FIG. 2, and both of the side plates are seen in FIG. 5. AsIcan be seen in FIG. 5, the links 53, 47 and 49 are twin links in thateach of these links comprises a pair of spaced link members. As is bestseen in FIG. 6, the other leg of the angle-link 49 is provided with aslot 65 therein for receiving a pin 67 that also extends through anopening 69 in a releasable cradle member or trip member 71. The pin 67moves in the slot 65 and opening 69 permitting relative movement betweenthe angle-link 49 and the trip member 71 during tripping and resettingoperations. The trip member 71 is pivotally supported, intermediate theends thereof, on and between the side plates 64, by means of a pin 73.The trip member 71 is maintained in the lat-ched position seen in FIG. 2by means of the trip device 27.

The trip device 27 comprises a latch member 75 that is pivotallysupported, intermediate the ends thereof, between the side plates 64 ona pin 77. The latch member 75 is biased in an unlatching(counterclockwise FIG. 2) direction by means of a torsion spring 79. Theupper end of the latch 75 engages the trip member 71 to latch the tripmember 71 in the position seen in FIG. 2. The lower end of the latchmember 75 is latched by means of a latch member 81 that is pivotallysupported intermediate the ends thereof on a pin 83 that is supportedbetween the side plates 64. The latch member 81 is biased in a latching(clockwise FIG. 2) direction about the pin 83 by means of a torsionspring 85. A calibrating screw 87 is threadedly supported on one end ofthe latch member 81.

In the closed position of the circuit breaker 5, a circuit extends fromthe plug-in line terminal 37 through the conductor 33, stationarycontact 29, movable contact 31, Contact arm 39, parallel flexibleconductors 89 and 91, parallel conducting paths 93 and 95, through thelefthand (FIG. 2) part of the conductor 93 to a conducting line that maybe connected to the conductor 93 by means of the clamp-type terminalconnector 19. The conductor 93 is a rigid conductor that is lixedlysecured in the housing 7. As can be seen in FIG. 2, the rigid conductor93 rests on a generally Hat part of the base above the cavity 35. Aflexible pad 99 is placed over the conductor 93, and when the housingcover 13 is tightly riveted down against the base 11 the pad 99 andrigid conductor 93 are sandwiched between the cover 13 and base 11 sothat the clamping force of the rivets (FIG. 5) operates to xedly securethe rigid conductor 93 within the housing. The main conducting pathbetween the contact arm 39 and clamp-type terminal 19 is through therigid conductor 93. A parallel conducting path is provided through theflexible conductor 91 and bimetal 95 to heat the bimetal 95 to thermallytrip the circuit breaker in a manner to be hereinafter specificallydescribed. As can be seen in FIG. 2, the bimetal 95 is supported at theleft end thereof on the rigid conductor 93, and the free end of thebimetal 95 is free to flex in an upward (FIG. 2) direction to trip thecircuit breaker.

Referring to FIG. 2, it will be noted that the housing is provided withan opening in the front thereof. A handle port of an insulatingoperating member 107 protrudes through the opening to permit manualoperation of the circuit breaker. The insulating operating member 107 ispivotally supported on the side plates 64 by means of a pin 109. Atorsion spring 113 biases the operating member 107 in a clockwise (FIG.2) direction. A link member 115 is pivotally connected, at one endthereof, to the knee 61 of the toggle 47. The link 115 is pivotallyconnected at the other end thereof to the lower end of the operatingmember 107 by means of a pin 117. The pin 117 moves in an opening 119 inthe trip member 71.

The circuit breaker is shown in FIG. 2 in the closed position with agenerally L-shaped insulating member 121 insulating the rigid conductor33 from the conductors that are positioned above the insulating member121. A coil compression spring 123 is positioned under the rigidconductor 33 to bias the conductor 33 upward to provide contact pressurebetween the contacts 29, 31 in the closed position of the contacts. Thehousing base is provided with an insulating projection 125 that extendsinto an opening in the conductor 33 to prevent substantial lateralmovement of the conductor 33. Upward movement of the conductor 33 islimited by an insulating member 200 that is held down by the plates 64that are in turn held down by the cover 13. An arc-extinguishingstructure 127 is provided for extinguishing arcs drawn between thecontacts during opening operations.

The circuit breaker is shown in the closed position in FIG. 2. When itis desired to manually operate the circuit breaker to the open position,the operating member 107 is pivoted from the on position seen in FIG. 2to the off position seen in FIG. 3. During this movement, the operatingmember 107 operates through the link 115 to move the knee 61 of thetoggle 47 to the left whereupon the erected toggle 47 collapses movingthe contact arm 39, toggle 47, link 115 and operating member 107 to theopen position seen in FIG. 3. The opening operation is eifected by theforce of the worker manually moving the operating member 107 which forceis aided by the forces of the springs 123, 45 and 113. During theopening operation, as the toggle 47 starts to collapse the spring 45 rstmoves the contact arm 39 to the position where the pin 43 is at thelower point of the slot 41 during which movement the heel part of themovable contact 31 first separates from the stationary contact 29, andwhen the pin 43 engages the contact arm at the bottom of the slot 41 theinal movement of the contact arm 39 is counterclockwise about the pin 43during which movement the toe portion of the movable contact 31separates from the stationary contact 29 and during which movement thecontact arm 39 pivots about the pin 43 to the fully open position seenin FIG. 3.

When it is desired to manually operate the circuit breaker to the closedposition, the operating member 107 is manually operated from the offposition (FIG. 3) to the on position (FIG. 2). During this movement, thelink 115 is driven by the operating member 107 to operate the toggle 47from the collapsed to the erected position. The link 115, which ispivotally connected at one end thereof to the operating member 107 bymeans of the pin 117 and at the other end thereof to the knee pivot 61of the toggle 47, serves as a thrust-transmitting connection between theoperating member 107 and the knee pivot 61 of the toggle 47. During theinitial part of this movement, the contact arm 39 pivots about the pin43 until the toe of the contact 31 engages the stationary contact 29whereupon further closing movement of the toggle 47 operates to move thecontact arm 39 to the fully closed position, wherein both the toe andheel of the contact 31 engage the stationary contact 29, during whichmovement the left (FIG. 2) end of the contact arm 39 is moved downward,as the slot 41 moves relative -t?) the stationary pivot pin 43, to thefully closed position.

During the manual opening and closing operations of the circuit breaker,the angle-link 51 is stationary to maintain the pivot 59 of the uppertoggle link 55 Xed.

The circuit breaker is tripped open by operation of the trip device 27.In addition to the bimetal 95, the trip device 27 comprises a U-shapedmagnetic member 127 supported with the bight portion thereof in a cavity129 in the base 11 and with the opposite legs thereof extending upwardon opposite sides of the rigid conductor 93 and on opposite sides of thebimetal 95. The latch member 81 is magnetic and the left-hand (FIG. 2)end of this member is positioned above the opposite legs of the member127 whereby the member 81 functions as an armature of an electromagnetictrip structure. An alternative construction would be to make the latchmember 81 non-magnetic and to secure a magnetic member to the member 81above the member 127.

Upon the occurrence of an overload above a first predetermined value andbelow a second predetermined value, the bimetal 95, which is heated bythe heat generated by the current ow therein and which is also heated bythe heat generated in the rigid conductor 93, eXes with the free end (onthe right) moving upward to engage the Calibrating screw 87 to move thelatch member 81 in a counterclockwise direction to release the latchmember 75. Upon release of the latch member 75, the trip member 71 isreleased and the contact arm 39 is free to move to the open positionunder the bias of the spring 45. Although the main tripping force isexerted by the spring 45, the contact pressure spring 123 providesadditional force during the initial movement, and the relatively weakspring 113 also aids in providing an opening force. The blow-off forcesgenerated by the arc also aid the tripping movement. The contact arm 39moves from the position shown in FIG. 2 to the tripped position shown inFIG. 4 with the trip member 71 moving clockwise und with the angle-link51 moving counterclockwise to permit the upper pivot 59 of the toggle 47to move to release the toggle 47 which collapses to the tripped positionseen in FIG. 4. During the tripping operation, the spring 113 operatesto move the operating member 107 to a tripped position (FIG. 4)intermediate the on and off positions. The operating member 107 isstopped in the tripped position by engagement of the pin 117 with anedge of the trip member 71 in the slot 119. When it is desired to resetthe circuit breaker for manual operation, the operating member 107 ismoved from the tripped position seen in FIG. 4 to a position slightlypast the` full off position seen in FIG. 3. During this movement, thepin 117 engages the trip member 71 in the slot 119 to rotate the tripmember 71 in a counterclockwise direction. Near the end of this movementof the operating member 107, the end of the trip member 71 engages thelatch member 75 moving the latch member clockwise to the latchingposition, and when the latch member 75 reaches the latching position thespring 85 biases the latch member 81 to the latching position to latchthe latch member 75 whereby upon release of the operating member 107 thecircuit breaker will be latched in the position seen in FIG. 3. When thetrip member 71 is in the latched position the angle-link 51 is heldstationary so that the upper pivot 59 of the toggle 47 is Xed -wherebythe circuit breaker may be manually operated between the on and offpositions in the same manner hereinbefore described. The slot-and-pinconnection between the angle-link 51 and trip member 71 preventsmovement of the angle-link 51 when the trip member is latched in astationary position and permits the relative movement between theseparts during the tripping and resetting operations. The angle-link 51enables a tripping operation of the trip member 71 with the trip member71 not moving to a position substantially higher within the circuitbreaker housing than the original position of the trip 6 member 71 sothat the height-wise dimension of the circuit breaker housing can bekept compact.

Upon the occurrence of an overload above the second predetermined value,magnetic flux generated in the members 127, 81 by means of the currentflowing through the members `93, causes attraction of the armature 81 tothe yoke 127 whereupon the armature 81 moves to the tripped positioninstantaneously without the time delay of the thermal trippingoperation. Upon movement of the latch member 81 to the tripped positionthe circuit breaker is tripped in the same manner as was hereinbeforedescribed with regard to the thermal tripping operation. The circuitbreaker is thereafter reset in the same manner as was hereinbeforedescribed with regard to the resetting operation following the thermaltripping operation.

As was previously set forth, the circuit breaker 5 is a two pole circuitbreaker With each of the poles constructed as shown in FIGS. 2-6. Ahandle tie member (FIGS. 1 and 5) connects the handles of the two pole-units together for simultaneous manual operation. In order to providethat Iboth of the pole units will trip upon the tripping of either ofthe pole units, a separate member 137 (FIG. 2) is pivotally mountedbetween the side plates 64 of each of the poles. Each of the members 137is pivotally supported on a pin 139. The members 137 in the two poleunits are operatively connected for simultaneous pivotal movement aboutthe same aXis. Upon the occurrence of a tripping operation in eitherpole unit, the associated latch 75 will engage the associated member 137to cam the member 137 in a counterclockwise (FIG. 2) `directionwhereupon both of the members 137 will simultaneously movecounterclockwise so that the member 137 in the adjacent pole unit willengage that armature 81 to move the armature 81 in the adjacent poleunit to the tripped position. When the circuit breaker is reset, thearmatures `81 engage the members 137 to move the members 137 to theposition shown in FIG. 2.

lIn the preferred embodiment, the operating member 107 is moved to anintermediate position during tripping operations to provide a visualindication that the circuit breaker is tripped. In this embodiment, itis necessary to reset the circuit breaker in the manner hereinbeforedescribed in order to manually operate the breaker after each trippingoperation. If it is desired to provide an automatic-reset circuitbreaker, the spring 113 is merely strengthened to provide enough driveduring a tripping operation to force the operating member 107 to thereset position. With the strengthened spring mounted in the breaker, theoperating member 107 will be automatically moved to the reset positionduring tripping operations. Thus, after tripping operations, the breakerwill be automatically reset and a worker will be able to manuallyoperate the breaker without manually resetting the breaker.

We claim as our invention:

1. A circuit breaker comprising a stationary contact, a movable contact,a contact arm carrying said movable contact, a latched trip structure, atoggle comprising a first link pivotally connected to said contact armand a second link pivotally connected to said latched trip structure, aknee pivot pivotally connecting said rst and second links, a manuallyoperable operating member, a thrust-transmitting connection between saidoperating member and said knee pivot, said operating member beingmanually movable to a closed position to operate through saidthrust-transmitting connection to erect said toggle to thrust saidcontact arm to the closed position, said operating member being operableto an open position to move said contact arm to the open position, tripmeans latching said latched trip structure and operating automaticallyupon the occurrence of certain overload current conditions to release,said latched trip structure, upon release of said latched tripstructure said latched trip structure and said toggle moving to atripped position to etfect automatic opening of said contacts, and meansoperating automatically upon release of said latched trip structure tomove said operating member to a tripped position intermediate saidclosed and opened positions to provide a visual indication that saidcircuit breaker has tripped.

2. A circuit breaker according to claim 1, said operating member beingmanually movable from said intermediate position to a reset position toreset said trip structure in a position wherein said trip means latchessaid trip structure to enable manual operation of said operating memberfollowing a tripping operation.

3. A circuit breaker according to claim 2, said operating member' beingpivotally mounted on a fixed pivot, and said thrust transmittingconnection comprising a link member pivotally connected at one endthereof to said operating member and at the Aother end thereof to saidknee pivot. v

4. A circuit breaker according to claim 3, said latched trip structurecomprising an elongated trip member pivotally supported intermediate theends thereof and an angle-link, said angle-link comprising a pivot partand a pair of legs extending from said pivot part at an angle, meanspivotally supporting said angle-link at said pivot part, said trip meanslatching one end of said releasable member, means operatively connectingthe other end of said releasable member with a first leg of saidangle-link, means pivotally connecting the second leg of said anglelinkto said second link, in the latched position of said trip structure saidtrip member and said angle-link remaining stationary during manualoperations of sai-d circuit breaker, and upon release of said tripstructure said trip member and said angle-link moving to permit movementof said toggle to thereby permit automatic opening of said contacts.

5. A circuit breaker according to claim 4, and said connection betweensaid trip member and said angle-link comprising a slot-and-pinconnection permitting lost motion between said trip member and saidangle-link.

6. A circuit breaker comprising a stationary contact, a movable contact,a contact arm carrying said movable Contact, a latched trip structurecomprising an elongated trip member and an angle-link, means pivotallysupporting said elongated trip member intermediate the ends thereof,said angle-link comprising a pivot part and a pair of legs extendingfrom said pivot part at an angle, means pivotally supporting saidangle-link at said pivot part, trip means latching one end of said tripmember, means operatively connecting the other end of said trip memberto a iirst leg of said angle-link, a toggle comprising a first linkpivotally connected to said contact arm and a second link pivotallyconnected to the second leg of said angle-link, a knee pivot pivotallyconnecting said irst and second links, a manually operable operatingmember, a thrust transmitting connection between said operating memberand said knee pivot, said operating member being movable to a closedposition to operate through said thrust transmitting connection to erectsaid toggle to thrust said -contact arm to the closed position, saidoperating member being movable to an open position to move said contactarm to the open position, said trip means operating upon the occurrenceof certain overload current conditions to release said trip member, andupon release of said trip member said trip member and said angle-linkmoving to permit movement of said toggle to permit movement of saidcontact arm to an open position.

7. A circuit breaker according to claim 6, said connection between saidtrip member and said first leg of said angle-link comprising a lostmotion connection connecting said trip member and angle-link with lostmotion.

8. A circuit breaker according to claim 6, spring means comprising atorsion spring member engaging said contact arm and biasing said contactarm to move said contact arm to the open position upon release of saidtrip member.

9. A circuit breaker according to claim 6, means operating automaticallyto move said operating member to a tripped position intermediate saidopen and closed positions upon release of said trip member, saidoperating member being movable from said intermediate position to saidopen position to reset said trip structure in a position wherein saidtrip member is latched by said trip means, and said trip member and saidangle-link in the reset position remaining stationary during manualopening and closing operations of said circuit breaker.

10. A circuit breaker according to claim 9, and said connection betweensaid trip member and said lirst leg of said angle-link comprising a lostmotion connection.

References Cited UNITED STATES PATENTS 2,329,053 9/1943 Jennings 335-232,170,412 8/1939 JenningS 335-36 3,251,232 5/1966 Harper 335-1743,384,845 5/1968 Johnson 335-23 3,391,357 7/1968 Heft 337-72 BERNARD A.GILHEANY, Primary Examiner H. BROOME, Assistant Examiner U.S. Cl. X.R.335-21, 27; 337-72

